On the Poinsot Construction*

When the polhode rolls on the herpolhode
invariably in the plane,
the forces tend to be free.

When the polhode slips on the herpolhode,
the forces are not mundane,
they're nonholonomic, you see!

*Inspired by a footnote to a discussion of the free rotation of a rigid body about its center of mass in Goldstein's Classical Mechanics, "Hence the jabberwockian sounding statement: the polehode rolls without slipping on the herpolhode lying in the invariable plane."

Copyright © 1974, 1999 by David N. Williams

There's a Polhode, Inc., which has information on the Purdue Compiler Construction Tool Set, and some physics links.

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